George Zimmerman Boxing Match -- Beefing Up Security ... We're Afraid For His Life

George Zimmerman's celebrity boxing match will be held in a secret location FILLED with security --and it's all being done to protect George from vengeful foes.

We're told there will only be 100 people present. Some will be "celebrities" and reporters. The promoter is worried if the venue becomes public ... someone will do to George what he did to Trayvon.

The event will be seen online ... through a paid subscription.

As we previously reported ... both the Game and DMX wanna go toe-to-toe with Trayvon Martin's killer in March.